U.S. patent number 10,913,604 [Application Number 15/972,569] was granted by the patent office on 2021-02-09 for system and method for queuing robots destined for one or more processing stations.
The grantee listed for this patent is Locus Robotics Corp.. Invention is credited to Kaitlin Margaret Gallagher, Luis Jaquez, Michael Charles Johnson, Sean Johnson.
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United States Patent |
10,913,604 |
Gallagher , et al. |
February 9, 2021 |
System and method for queuing robots destined for one or more
processing stations
Abstract
A method for queuing robots destined for one or more processing
stations in an environment includes determining when each robot of
a plurality of robots destined for the one or more processing
stations have entered a predefined target zone proximate the one or
more processing stations. The method also includes assigning each
of the robots to one of a plurality of queue positions based on an
assigned priority and directing each of the robots from its
assigned queue position to a processing position of one of the
processing stations. Each of the processing stations includes at
least two processing positions for a like number of robots to
occupy for processing by an operator.
Inventors: |
Gallagher; Kaitlin Margaret
(Lawrence, MA), Johnson; Sean (Danvers, MA), Johnson;
Michael Charles (Ashland, MA), Jaquez; Luis (Burlington,
MA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Locus Robotics Corp. |
Wilmington |
MA |
US |
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Family
ID: |
1000005350019 |
Appl.
No.: |
15/972,569 |
Filed: |
May 7, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180370728 A1 |
Dec 27, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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15628751 |
Jun 21, 2017 |
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15697759 |
Sep 7, 2017 |
10513033 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J
9/1666 (20130101); B25J 5/007 (20130101); G05D
1/0297 (20130101); G06Q 10/087 (20130101); B66F
9/063 (20130101); B65G 1/1373 (20130101); G05D
1/0291 (20130101); B65G 1/0492 (20130101); G05D
1/0234 (20130101); G05D 1/0274 (20130101); B25J
9/0084 (20130101); G06Q 10/00 (20130101); Y10S
901/01 (20130101); G05D 2201/0216 (20130101); Y10S
901/08 (20130101) |
Current International
Class: |
B65G
1/137 (20060101); B66F 9/06 (20060101); B25J
5/00 (20060101); G05D 1/02 (20200101); G06Q
10/00 (20120101); B25J 9/16 (20060101); B25J
9/00 (20060101); G06Q 10/08 (20120101); B65G
1/04 (20060101) |
References Cited
[Referenced By]
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Foreign Patent Documents
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102915465 |
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103217979 |
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Jul 2013 |
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1049500684 |
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Sep 2015 |
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102016893 |
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Apr 2018 |
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1632319 |
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Mar 2006 |
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EP |
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2617531 |
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Jul 2013 |
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EP |
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57204911 |
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Dec 1982 |
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H09-508740 |
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JP |
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P2000-250627 |
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JP |
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2006231448 |
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Oct 2007 |
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JP |
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2007149227 |
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Dec 2007 |
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WO |
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Other References
International Search Report with Written Opinion, dated Aug. 29,
2018, received in international patent application No.
PCT/US2018/038674, 10 pages. cited by applicant .
International Search Report with Written Opinion, dated Aug. 29,
2018, received in international patent application No.
PCT/US2018/038695,11 pages. cited by applicant .
Office Action issued by the Japanese Patent Office dated Jul. 1,
2020 in Japanese Patent Application No. 2018-550338, entitled
"Robot and Method for Queueing Robot for Order-Fulfillment
Operations." cited by applicant .
International Search Report with Written Opinion, dated Jun. 30,
2017, received in international patent application No.
PCT/US17/24194, 12 pages. cited by applicant.
|
Primary Examiner: Randazzo; Thomas
Attorney, Agent or Firm: Verrill Dana, LLP Powell; John
W.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part application of U.S.
application Ser. No. 15/628,751 filed on Jun. 21, 2017, and U.S.
application Ser. No. 15/697,759 filed on Sep. 7, 2017, the contents
of both are incorporated herein by reference in their entirety.
Claims
We claim:
1. A method for queuing robots destined for one or more processing
stations in an environment, the method comprising: establishing a
predefined target zone proximate the one or more processing
stations; determining when each robot of a plurality of robots
destined for the one or more processing stations has entered the
predefined target zone proximate the one or more processing
stations; assigning each of the robots to one of a plurality of
queue positions based on an assigned priority; and directing each
of the robots from its assigned queue position to a processing
position of one of the processing stations; wherein each of the
processing stations includes at least two processing positions for
a like number of robots to occupy for processing by an operator;
wherein the assigned priority is determined by both the order of
entry of each of the plurality of robots into the target zone and
an order priority associated with a customer order to be processed
by each of the plurality of robots.
2. The method of claim 1 wherein the environment is a warehouse
space containing items for customer order fulfillment.
3. The method of claim 1 wherein the order priority associated with
the customer order to be processed by each of the plurality of
robots is determined by one or more of the following: shipping
priority, item type, customer type, or retailer.
4. The method of claim 1 wherein the at least two processing
positions of the one or more processing stations and the plurality
of queue positions are each defined by a pose to which the robot is
capable of navigating.
5. The method of claim 1 wherein the one or more processing
stations are each configured for one of (a) inducting robots, (b)
unloading robots, and (c) both inducting and unloading robots.
6. The method of claim 1 wherein the plurality of queue positions
are grouped into one queue group and the plurality of queue
positions are associated with a plurality of processing
stations.
7. The method of claim 6 wherein the robots from the one queue
group are directed in priority order to a next available processing
position from any of the plurality of processing stations.
8. The method of claim 1 wherein the plurality of queue positions
include at least two queue groups spaced from each other in the
environment.
9. The method of claim 8 wherein the first plurality of queue
positions in the first queue group and the second plurality of
queue positions in the second queue group are associated with a
plurality of processing stations.
10. The method of claim 9 wherein the robots from the first and
second queue groups are directed in priority order to a next
available processing position from any of the plurality of
processing stations.
11. The method of claim 8 including a first plurality of queue
positions in a first queue group and a second plurality of queue
positions in a second queue group, wherein the first plurality of
queue positions in the first queue group and the second plurality
of queue positions in a second queue group are all associated with
one processing station.
12. The method of claim 11 wherein the one processing station
includes a first processing position and a second processing
position.
13. The method of claim 12 wherein robots from the first queue
group are directed to the first processing position and robots from
the second queue group are directed to the second processing
position.
14. The method of claim 13 wherein robots which have entered the
target zone destined for the one processing station are each
assigned a priority and are directed to one of the first queue
group or the second queue group in an alternating manner based on
priority starting with the highest priority robot being assigned to
the first queue group.
15. The method of claim 14 wherein robots from the first queue
group are directed to the first processing position in sequence
based on priority and robots from the second queue group are
directed to the second processing position in sequence based on
priority.
16. A system for queuing robots destined for at least one
processing station in an environment, the system comprising: a
plurality of robots; at least one processing station configured for
processing the plurality of robots; wherein each of the at least
one processing station includes at least two processing positions
for a like number of robots to occupy for processing by an
operator; and a management system in communication with the
plurality of robots and the at least one processing station, the
management system configured to: establish a predefined target zone
proximate the one or more processing station, determine when each
robot of a plurality of robots destined for the at least one
processing station has entered a predefined target zone proximate
the at least one processing station, assign each of the robots to
one of a plurality of queue positions based on an assigned
priority, direct each of the robots from its assigned queue
position to a processing position of one of the at least one
processing stations; and wherein the assigned priority is
determined by both the order of entry of each of the plurality of
robots into the target zone and an order priority associated with a
customer order to be processed by each of the plurality of
robots.
17. The system of claim 16 wherein the environment is a warehouse
space containing items for customer order fulfillment.
18. The system of claim 16 wherein the order priority associated
with the customer order to be processed by each of the plurality of
robots is determined by one or more of the following: shipping
priority, item type, customer type, or retailer.
19. The system of claim 16 wherein the at least two processing
positions of the one or more processing stations and the plurality
of queue positions are each defined by a pose to which the robot is
capable of navigating.
20. The system of claim 16 wherein the one or more processing
stations are each configured for one of (a) induction, (b) packing,
and (c) both induction and packing.
21. The system of claim 16 wherein the plurality of queue positions
are grouped into one queue group and the plurality of queue
positions are associated with a plurality of processing
stations.
22. The system of claim 21 wherein the robots from the one queue
group are directed in priority order to a next available processing
position from any of the plurality of processing stations.
23. The system of claim 16 wherein the plurality of queue positions
include at least two queue groups spaced from each other in the
environment.
24. The system of claim 23 wherein the first plurality of queue
positions in the first queue group and the second plurality of
queue positions in the second queue group are associated with a
plurality of processing stations.
25. The system of claim 24 wherein the robots from the first and
second queue groups are directed in priority order to a next
available processing position from any of the plurality of
processing stations.
26. The system of claim 23 including a first plurality of queue
positions in a first queue group and a second plurality of queue
positions in a second queue group, wherein the first plurality of
queue positions in the first queue group and the second plurality
of queue positions in a second queue group are all associated with
one processing station.
27. The system of claim 26 wherein the one processing station
includes a first processing position and a second processing
position.
28. The system of claim 27 wherein robots from the first queue
group are directed to the first processing position and robots from
the second queue group are directed to the second processing
position.
29. The system of claim 28 wherein robots which have entered the
target zone destined for the one processing station are each
assigned a priority and are directed to one of the first queue
group or the second queue group in an alternating manner based on
priority starting with the highest priority robot being assigned to
the first queue group.
30. The system of claim 29 wherein robots from the first queue
group are directed to the first processing position in sequence
based on priority and robots from the second queue group are
directed to the second processing position in sequence based on
priority.
Description
FIELD OF THE INVENTION
This invention relates to a system and method for queueing robots
destined for processing stations and more particularly to directing
each robot from a queue to one of a plurality of processing
positions at each processing station.
BACKGROUND OF THE INVENTION
Ordering products over the internet for home delivery is an
extremely popular way of shopping. Fulfilling such orders in a
timely, accurate and efficient manner is logistically challenging
to say the least. Clicking the "check out" button in a virtual
shopping cart creates an "order." The order includes a listing of
items that are to be shipped to a particular address. The process
of "fulfillment" involves physically taking or "picking" these
items from a large warehouse, packing them, and shipping them to
the designated address. An important goal of the order-fulfillment
process is thus to ship as many items in as short a time as
possible.
The order-fulfillment process typically takes place in a large
warehouse that contains many products, including those listed in
the order. Among the tasks of order fulfillment is therefore that
of traversing the warehouse to find and collect the various items
listed in an order. In addition, the products that will ultimately
be shipped first need to be received in the warehouse and stored or
"placed" in storage bins in an orderly fashion throughout the
warehouse so they can be readily retrieved for shipping.
In a large warehouse, the goods that are being delivered and
ordered can be stored in the warehouse very far apart from each
other and dispersed among a great number of other goods. With an
order-fulfillment process using only human operators to place and
pick the goods requires the operators to do a great deal of walking
and can be inefficient and time consuming. Since the efficiency of
the fulfillment process is a function of the number of items
shipped per unit time, increasing time reduces efficiency.
In order to increase efficiency, robots may be used to perform
functions of humans or they may be used to supplement the humans'
activities. For example, robots may be assigned to "place" a number
of items in various locations dispersed throughout the warehouse or
to "pick" items from various locations for packing and shipping.
The picking and placing may be done by the robot alone or with the
assistance of human operators. For example, in the case of a pick
operation, the human operator would pick items from shelves and
place them on the robots or, in the case of a place operation, the
human operator would pick items from the robot and place them on
the shelves.
With numerous robots navigating a warehouse space it is very
possible and even likely that robots will attempt to navigate to a
position that is occupied by another robot, resulting in a race
condition. Race conditions are when two robots are attempting to
get to the same place and become processor bound as they attempt to
reconcile the changing external environment. Race conditions are
very undesirable and can result the robots being unable to perform
further operations until the condition is resolved.
Another aspect of autonomous robot solutions in warehouse order
fulfillment operations that can result in inefficiencies is the
process of assigning orders to robots and in the process of
removing orders from robots for packing and shipping to customers.
This is typically done with the assistance of a human operator. The
process of assigning orders is referred to as an "induction"
process and may include assigning to a robot one or more "pick"
orders (items to be picked for shipping to a customer) or it may
include assigning one or more "place" orders (items to be placed
into inventory in the appropriate location in the warehouse). The
process of removing orders from robots which have been picked so
that items can be packed by an operator and shipped to customers is
called "packing". In a warehouse there may be a number of induction
stations and a number of packing stations to which the robots can
travel to be assigned orders or to deliver completed orders to be
packed and shipped.
With many robots operating in a warehouse, coordinating a smooth an
efficient process for access to common induction and packing
stations while avoiding race conditions between robots is a complex
task. However, processing robots at induction and packing stations
effectively and efficiently is a critical part of ensuring high
throughput of orders in the warehouse operation. Therefore, there
exists a need for improving the efficiency and effectiveness of
processing robots (induction and packing) to increase
throughput.
BRIEF SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a smooth an
efficient process for robots to access common induction and packing
stations.
It is a further an object of the invention to provide such a
process which avoids race conditions between robots while accessing
common induction and packing stations.
It is a further an object of the invention to decreases processing
time at induction/packing stations and hence waiting time for
robots to increase throughput of the warehouse operation.
In one aspect the invention features a method for queuing robots
destined for one or more processing stations in an environment. The
method includes determining when each robot of a plurality of
robots destined for the one or more processing stations has entered
a predefined target zone proximate the one or more processing
stations and assigning each of the robots to one of a plurality of
queue positions based on an assigned priority. The method also
includes directing each of the robots from its assigned queue
position to a processing position of one of the processing
stations, wherein each of the processing stations includes at least
two processing positions for a like number of robots to occupy for
processing by an operator.
In other aspects of the invention one or more of the following
features may be included. The environment may be a warehouse space
containing items for customer order fulfillment. The assigned
priority may be determined by the order of entry of each of the
plurality of robots into the target zone, and the first robot to
enter the target zone may be assigned the highest priority. The
assigned priority may be determined by one or both of the order of
entry of each of the plurality of robots into the target zone and
an order priority associated with a customer order to be processed
by each of the plurality of robots. The order priority associated
with the customer order to be processed by each of the plurality of
robots may be determined by one or more of the following: shipping
priority, item type, customer type, or retailer. The plurality of
queue positions may include at least two queue groups spaced from
each other in the environment. The method may include a first
plurality of queue positions in a first queue group and a second
plurality of queue positions in a second queue group, wherein the
first plurality of queue positions in the first queue group and the
second plurality of queue positions in a second queue group are all
associated with one processing station. The plurality of queue
positions may be grouped into one queue group and the plurality of
queue positions are associated with a plurality of processing
stations. The first plurality of queue positions in the first queue
group and the second plurality of queue positions in the second
queue group may be associated with a plurality of processing
stations. The at least two processing positions of the one or more
processing stations and the plurality of queue positions may each
defined by a pose to which the robot is capable of navigating.
In further aspects of the invention one or more of the following
features may be included. The one processing station may include a
first processing position and a second processing position. Robots
from the first queue group may be directed to the first processing
position and robots from the second queue group may be directed to
the second processing position. Robots which have entered the
target zone destined for the one processing station may each be
assigned a priority and are directed to one of the first queue
group or the second queue group in an alternating manner based on
priority starting with the highest priority robot being assigned to
the first queue group. Robots from the first queue group may be
directed to the first processing position in sequence based on
priority and robots from the second queue group may be directed to
the second processing position in sequence based on priority. The
one or more processing stations may each be configured for one of
(a) induct robots, (b) unloading robots, and (c) both inducting and
unloading robots. Robots from the one queue group may be directed
in priority order to a next available processing position from any
of the plurality of processing stations. Robots from the first and
second queue groups may be directed in priority order to a next
available processing position from any of the plurality of
processing stations.
In yet another aspect, the invention features a system for queuing
robots destined for at least one processing station in an
environment. The system includes a plurality of robots and at least
one processing station configured for processing the plurality of
robots. Each of the at least one processing station includes at
least two processing positions for a like number of robots to
occupy for processing by an operator. There is a management system
in communication with the plurality of robots and the at least one
processing station. The management system is configured to
determine when each robot of a plurality of robots destined for the
at least one processing station has entered a predefined target
zone proximate the at least one processing station. The management
system is also configured to assign each of the robots to one of a
plurality of queue positions based on an assigned priority and to
direct each of the robots from its assigned queue position to a
processing position of one of the at least one processing
stations.
In other aspects of the invention one or more of the following
features may be included. The environment may be a warehouse space
containing items for customer order fulfillment. The assigned
priority may be determined by the order of entry of each of the
plurality of robots into the target zone, and the first robot to
enter the target zone may be assigned the highest priority. The
assigned priority may be determined by one or both of the order of
entry of each of the plurality of robots into the target zone and
an order priority associated with a customer order to be processed
by each of the plurality of robots. The order priority associated
with the customer order to be processed by each of the plurality of
robots may be determined by one or more of the following: shipping
priority, item type, customer type, or retailer. The plurality of
queue positions may include at least two queue groups spaced from
each other in the environment. The method may include a first
plurality of queue positions in a first queue group and a second
plurality of queue positions in a second queue group, wherein the
first plurality of queue positions in the first queue group and the
second plurality of queue positions in a second queue group may be
all associated with one processing station. The plurality of queue
positions may be grouped into one queue group and the plurality of
queue positions may be associated with a plurality of processing
stations. The first plurality of queue positions in the first queue
group and the second plurality of queue positions in the second
queue group may be associated with a plurality of processing
stations.
In yet further aspects of the invention one or more of the
following features may be included. The at least two processing
positions of the one or more processing stations and the plurality
of queue positions may each be defined by a pose to which the robot
is capable of navigating. The one processing station may include a
first processing position and a second processing position. Robots
from the first queue group may be directed to the first processing
position and robots from the second queue group may be directed to
the second processing position. Robots which have entered the
target zone destined for the one processing station may be each
assigned a priority and may be directed to one of the first queue
group or the second queue group in an alternating manner based on
priority starting with the highest priority robot being assigned to
the first queue group. Robots from the first queue group may be
directed to the first processing position in sequence based on
priority and robots from the second queue group may be directed to
the second processing position in sequence based on priority. The
one or more processing stations may each be configured for one of
(a) induction, (b) packing, and (c) both induction and packing.
Robots from the one queue group may be directed in priority order
to a next available processing position from any of the plurality
of processing stations. Robots from the first and second queue
groups may be directed in priority order to a to a next available
processing position from any of the plurality of processing
stations.
These and other features of the invention will be apparent from the
following detailed description and the accompanying figures, in
which:
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a top plan view of an order-fulfillment warehouse;
FIG. 2A is a front elevational view of a base of one of the robots
used in the warehouse shown in FIG. 1;
FIG. 2B is a perspective view of a base of one of the robots used
in the warehouse shown in FIG. 1;
FIG. 3 is a perspective view of the robot in FIGS. 2A and 2B
outfitted with an armature and parked in front of a shelf shown in
FIG. 1;
FIG. 4 is a partial map of the warehouse of FIG. 1 created using
laser radar on the robot;
FIG. 5 is a flow chart depicting the process for locating fiducial
markers dispersed throughout the warehouse and storing fiducial
marker poses;
FIG. 6 is a table of the fiducial identification to pose
mapping;
FIG. 7 is a table of the bin location to fiducial identification
mapping;
FIG. 8 is a flow chart depicting product SKU to pose mapping
process;
FIG. 9 is a schematic view of the target and queue locations used
in the queuing process according to an aspect of this
invention;
FIG. 10 is a flow chart depicting the robot queuing process
according to an aspect of this invention;
FIG. 11 is a schematic view of the target and queue locations
according to another aspect of this invention with robots being
directed to designated queue locations based on assigned
priorities;
FIG. 12 is a schematic view of the target and queue locations in
another aspect of queuing process according to this invention in
which a shared queue is used;
FIG. 13 is a schematic view of the target and queue locations in
another aspect of queuing process according to this invention in
which both a shared queue and split queue are used;
FIG. 14 is a schematic view of another aspect of the queuing
process according to this invention in which a split queue is used
to feed a processing station having multiple processing
positions;
FIG. 15 is a schematic view of another aspect of the queuing
process according to this invention in which a shared queue is used
to feed multiple processing stations each having multiple
processing positions;
FIG. 16 is a schematic view of another aspect of the queuing
process according to this invention in which the shared queue
according to FIG. 15 is split and is used to feed a multiple
processing station each having multiple processing positions;
and
FIG. 17 is a schematic view of another aspect of the queuing
process according to this invention in which the split queue
according to FIG. 14 is split and is used to feed a multiple
processing stations each having multiple processing positions.
DETAILED DESCRIPTION OF INVENTION
The disclosure and the various features and advantageous details
thereof are explained more fully with reference to the non-limiting
embodiments and examples that are described and/or illustrated in
the accompanying drawings and detailed in the following
description. It should be noted that the features illustrated in
the drawings are not necessarily drawn to scale, and features of
one embodiment may be employed with other embodiments as the
skilled artisan would recognize, even if not explicitly stated
herein. Descriptions of well-known components and processing
techniques may be omitted so as to not unnecessarily obscure the
embodiments of the disclosure. The examples used herein are
intended merely to facilitate an understanding of ways in which the
disclosure may be practiced and to further enable those of skill in
the art to practice the embodiments of the disclosure. Accordingly,
the examples and embodiments herein should not be construed as
limiting the scope of the disclosure. Moreover, it is noted that
like reference numerals represent similar parts throughout the
several views of the drawings.
The invention is directed to a system and method for queueing
robots destined for a common processing station. Although not
restricted to any particular robot application, one suitable
application that the invention may be used in is order fulfillment.
The use of robots in this application will be described to provide
context for the system and method for queueing robots but is not
limited to that application. Moreover, a specific autonomous mobile
robot ("AMR") implementation is described herein, but it is only to
provide context for the induction process according to this
invention. Any applicable robot design/system may be used in
conjunction with the induction process described herein.
Referring to FIG. 1, a typical order-fulfillment warehouse 10
includes shelves 12 filled with the various items that could be
included in an order. In operation, an incoming stream of orders 16
from warehouse management server 15 arrive at an order-server 14.
The order-server 14 may prioritize and group orders, among other
things, for assignment to robots 18 during an induction process. As
the robots are inducted by operators, at a processing station (e.g.
station 100), the orders 16 are assigned and communicated to robots
18 wirelessly for execution. It will be understood by those skilled
in the art that order server 14 may be a separate server with a
discrete software system configured to interoperate with the
warehouse management system server 15 and warehouse management
software or the order server functionality may be integrated into
the warehouse management software and run on the warehouse
management server 15.
In a preferred embodiment, a robot 18, shown in FIGS. 2A and 2B,
includes an autonomous wheeled base 20 having a laser-radar 22. The
base 20 also features a transceiver (not shown) that enables the
robot 18 to receive instructions from and transmit data to the
order-server 14 and/or other robots, and a pair of digital optical
cameras 24a and 24b. The robot base also includes an electrical
charging port 26 for re-charging the batteries which power
autonomous wheeled base 20. The base 20 further features a
processor (not shown) that receives data from the laser-radar and
cameras 24a and 24b to capture information representative of the
robot's environment. There is a memory (not shown) that operates
with the processor to carry out various tasks associated with
navigation within the warehouse 10, as well as to navigate to
fiducial marker 30 placed on shelves 12, as shown in FIG. 3.
Fiducial marker 30 (e.g. a two-dimensional bar code) corresponds to
bin/location of an item ordered. The navigation approach of this
invention is described in detail below with respect to FIGS. 4-8.
Fiducial markers are also used to identify charging stations
according to an aspect of this invention and the navigation to such
charging station fiducial markers is the same as the navigation to
the bin/location of items ordered. Once the robots navigate to a
charging station, a more precise navigation approach is used to
dock the robot with the charging station and such a navigation
approach is described below.
Referring again to FIG. 2B, base 20 includes an upper surface 32
where a tote or bin could be stored to carry items. There is also
shown a coupling 34 that engages any one of a plurality of
interchangeable armatures 40, one of which is shown in FIG. 3. The
particular armature 40 in FIG. 3 features a tote-holder 42 (in this
case a shelf) for carrying a tote 44 that receives items, and a
tablet holder 46 (or laptop/other user input device) for supporting
a tablet 48. In some embodiments, the armature 40 supports one or
more totes for carrying items. In other embodiments, the base 20
supports one or more totes for carrying received items. As used
herein, the term "tote" includes, without limitation, cargo
holders, bins, cages, shelves, rods from which items can be hung,
caddies, crates, racks, stands, trestle, containers, boxes,
canisters, vessels, and repositories.
Although a robot 18 excels at moving around the warehouse 10, with
current robot technology, it is not very good at quickly and
efficiently picking items from a shelf and placing them in the tote
44 due to the technical difficulties associated with robotic
manipulation of objects. A more efficient way of picking items is
to use a local operator 50, which is typically human, to carry out
the task of physically removing an ordered item from a shelf 12 and
placing it on robot 18, for example, in tote 44. The robot 18
communicates the order to the local operator 50 via the tablet 48
(or laptop/other user input device), which the local operator 50
can read, or by transmitting the order to a handheld device used by
the local operator 50.
Upon receiving an order 16 from the order server 14, the robot 18
proceeds to a first warehouse location, e.g. as shown in FIG. 3. It
does so based on navigation software stored in the memory and
carried out by the processor. The navigation software relies on
data concerning the environment, as collected by the laser-radar
22, an internal table in memory that identifies the fiducial
identification ("ID") of fiducial marker 30 that corresponds to a
location in the warehouse 10 where a particular item can be found,
and the cameras 24a and 24b to navigate.
Upon reaching the correct location (pose), the robot 18 parks
itself in front of a shelf 12 on which the item is stored and waits
for a local operator 50 to retrieve the item from the shelf 12 and
place it in tote 44. If robot 18 has other items to retrieve it
proceeds to those locations. The item(s) retrieved by robot 18 are
then delivered to a processing station 100, FIG. 1, where they are
packed and shipped. While processing station 100 has been described
with regard to this figure as being capable of inducting and
unloading/packing robots, it may be configured such that robots are
either inducted or unloaded/packed at a station, i.e. they may be
restricted to performing a single function.
It will be understood by those skilled in the art that each robot
may be fulfilling one or more orders and each order may consist of
one or more items. Typically, some form of route optimization
software would be included to increase efficiency, but this is
beyond the scope of this invention and is therefore not described
herein.
In order to simplify the description of the invention, a single
robot 18 and operator 50 are described. However, as is evident from
FIG. 1, a typical fulfillment operation includes many robots and
operators working among each other in the warehouse to fill a
continuous stream of orders.
The navigation approach of this invention, as well as the semantic
mapping of a SKU of an item to be retrieved to a fiducial ID/pose
associated with a fiducial marker in the warehouse where the item
is located, is described in detail below with respect to FIGS.
4-8.
Using one or more robots 18, a map of the warehouse 10 must be
created and the location of various fiducial markers dispersed
throughout the warehouse must be determined. To do this, one or
more of the robots 18 as they are navigating the warehouse they are
building/updating a map 10a, FIG. 4, utilizing its laser-radar 22
and simultaneous localization and mapping (SLAM), which is a
computational problem of constructing or updating a map of an
unknown environment. Popular SLAM approximate solution methods
include the particle filter and extended Kalman filter. The SLAM
GMapping approach is the preferred approach, but any suitable SLAM
approach can be used.
Robot 18 utilizes its laser-radar 22 to create map 10a of warehouse
10 as robot 18 travels throughout the space identifying, open space
112, walls 114, objects 116, and other static obstacles, such as
shelf 12, in the space, based on the reflections it receives as the
laser-radar scans the environment.
While constructing the map 10a (or updating it thereafter), one or
more robots 18 navigates through warehouse 10 using camera 26 to
scan the environment to locate fiducial markers (two-dimensional
bar codes) dispersed throughout the warehouse on shelves proximate
bins, such as 32 and 34, FIG. 3, in which items are stored. Robots
18 use a known starting point or origin for reference, such as
origin 110. When a fiducial marker, such as fiducial marker 30,
FIGS. 3 and 4, is located by robot 18 using its camera 26, the
location in the warehouse relative to origin 110 is determined.
By the use of wheel encoders and heading sensors, vector 120, and
the robot's position in the warehouse 10 can be determined. Using
the captured image of a fiducial marker/two-dimensional barcode and
its known size, robot 18 can determine the orientation with respect
to and distance from the robot of the fiducial
marker/two-dimensional barcode, vector 130. With vectors 120 and
130 known, vector 140, between origin 110 and fiducial marker 30,
can be determined. From vector 140 and the determined orientation
of the fiducial marker/two-dimensional barcode relative to robot
18, the pose (position and orientation) defined by a quaternion (x,
y, z, .omega.) for fiducial marker 30 can be determined.
Flow chart 200, FIG. 5, describing the fiducial marker location
process is described. This is performed in an initial mapping mode
and as robot 18 encounters new fiducial markers in the warehouse
while performing picking, placing and/or other tasks. In step 202,
robot 18 using camera 26 captures an image and in step 204 searches
for fiducial markers within the captured images. In step 206, if a
fiducial marker is found in the image (step 204) it is determined
if the fiducial marker is already stored in fiducial table 300,
FIG. 6, which is located in memory 34 of robot 18. If the fiducial
information is stored in memory already, the flow chart returns to
step 202 to capture another image. If it is not in memory, the pose
is determined according to the process described above and in step
208, it is added to fiducial to pose lookup table 300.
In look-up table 300, which may be stored in the memory of each
robot, there are included for each fiducial marker a fiducial
identification, 1, 2, 3, etc, and a pose for the fiducial
marker/bar code associated with each fiducial identification. The
pose consists of the x,y,z coordinates in the warehouse along with
the orientation or the quaternion (x,y,z, .omega.).
In another look-up Table 400, FIG. 7, which may also be stored in
the memory of each robot, is a listing of bin locations (e.g.
402a-f) within warehouse 10, which are correlated to particular
fiducial ID's 404, e.g. number "11". The bin locations, in this
example, consist of seven alpha-numeric characters. The first six
characters (e.g. L01001) pertain to the shelf location within the
warehouse and the last character (e.g. A-F) identifies the
particular bin at the shelf location. In this example, there are
six different bin locations associated with fiducial ID "11". There
may be one or more bins associated with each fiducial
ID/marker.
The alpha-numeric bin locations are understandable to humans, e.g.
operator 50, FIG. 3, as corresponding to a physical location in the
warehouse 10 where items are stored. However, they do not have
meaning to robot 18. By mapping the locations to fiducial ID's,
Robot 18 can determine the pose of the fiducial ID using the
information in table 300, FIG. 6, and then navigate to the pose, as
described herein.
The order fulfillment process according to this invention is
depicted in flow chart 500, FIG. 8. In step 502, from warehouse
management system 15, FIG. 1, order server 14 obtains an order,
which may consist of one or more items to be retrieved. It should
be noted that the order assignment process is fairly complex and
goes beyond the scope of this disclosure. One such order assignment
process is described in commonly owned U.S. patent application Ser.
No. 15/807,672, entitled Order Grouping in Warehouse Order
Fulfillment Operations, filed on Sep. 1, 2016, which is
incorporated herein by reference in its entirety. It should also be
noted that robots may have tote arrays which allow a single robot
to execute multiple orders, one per bin or compartment. Examples of
such tote arrays are described in U.S. patent application Ser. No.
15/254,321, entitled Item Storage Array for Mobile Base in Robot
Assisted Order-Fulfillment Operations, filed on Sep. 1, 2016, which
is incorporated herein by reference in its entirety.
Continuing to refer to FIG. 8, in step 504 the SKU number(s) of the
items is/are determined by the warehouse management system 15, and
from the SKU number(s), the bin location(s) is/are determined in
step 506. A list of bin locations for the order is then transmitted
to robot 18. In step 508, robot 18 correlates the bin locations to
fiducial ID's and from the fiducial ID's, the pose of each fiducial
ID is obtained in step 510. In step 512 the robot 18 navigates to
the pose as shown in FIG. 3, where an operator can pick the item to
be retrieved from the appropriate bin and place it on the
robot.
Item specific information, such as SKU number and bin location,
obtained by the warehouse management system 15/order server 14, can
be transmitted to tablet 48 on robot 18 so that the operator 50 can
be informed of the particular items to be retrieved when the robot
arrives at each fiducial marker location.
With the SLAM map and the pose of the fiducial ID's known, robot 18
can readily navigate to any one of the fiducial ID's using various
robot navigation techniques. The preferred approach involves
setting an initial route to the fiducial marker pose given the
knowledge of the open space 112 in the warehouse 10 and the walls
114, shelves (such as shelf 12) and other obstacles 116. As the
robot begins to traverse the warehouse using its laser radar 26, it
determines if there are any obstacles in its path, either fixed or
dynamic, such as other robots 18 and/or operators 50, and
iteratively updates its path to the pose of the fiducial marker.
The robot re-plans its route about once every 50 milliseconds,
constantly searching for the most efficient and effective path
while avoiding obstacles.
Generally, localization of the robot within warehouse 10a is
achieved by many-to-many multiresolution scan matching (M3RSM)
operating on the SLAM virtual map. Compared to brute force methods,
M3RSM dramatically reduces the computational time for a robot to
perform SLAM loop closure and scan matching, two critical steps in
determining robot pose and position. Robot localization is further
improved by minimizing the M3SRM search space according to methods
disclosed in related U.S. application Ser. No. 15/712,222, entitled
Multi-Resolution Scan Matching with Exclusion Zones, filed on Sep.
22, 2017 and incorporated by reference in its entirety herein.
With the product SKU/fiducial ID to fiducial pose mapping technique
combined with the SLAM navigation technique both described herein,
robots 18 are able to very efficiently and effectively navigate the
warehouse space without having to use more complex navigation
approaches typically used which involve grid lines and intermediate
fiducial markers to determine location within the warehouse.
Generally, navigation in the presence of other robots and moving
obstacles in the warehouse is achieved by collision avoidance
methods including the dynamic window approach (DWA) and optimal
reciprocal collision avoidance (ORCA). DWA computes among feasible
robot motion trajectories an incremental movement that avoids
collisions with obstacles and favors the desired path to the target
fiducial marker. ORCA optimally avoids collisions with other moving
robots without requiring communication with the other robot(s).
Navigation proceeds as a series of incremental movements along
trajectories computed at the approximately 50 ms update intervals.
Collision avoidance may be further improved by techniques described
in related U.S. application Ser. No. 15/712,256, entitled Dynamic
Window Approach Using Optimal Reciprocal Collision Avoidance
Cost-Critic, filed on Sep. 22, 2017 and incorporated by reference
in its entirety herein.
As described above, a problem that can arise with multiple robots
navigating a space is called a "race condition", which can occur if
one or more robots attempt to navigate to a space occupied by
another robot. With this invention, alternative destinations for
the robots are created to place them in a queue and avoid race
conditions from occurring. The process is depicted in FIG. 9, where
robot 600 is shown positioned at a target location/pose 602. Pose
602 could correspond to any location in a warehouse space, for
example, a packing station or a position near a particular bin.
When other robots try to navigate to pose 602, such as robots 604,
606, and 608 (as indicated by the dotted lines from the robots and
terminating at pose 602) they are redirected to temporary holding
locations, such as locations or queue slots 610, 612, and 614.
Queue slots or locations 610, 612, and 614 are offset from pose
612. In this example queue slot 610 is offset from pose 602 by a
distance x, which could be, for example, one (1) meter. Queue slot
612 is offset from queue slot 610 by an additional distance x and
queue slot 614 is offset another distance x from queue slot 612.
While, in this example, the distances are uniformly spaced along a
straight line emanating from pose 602, this is not a requirement of
the invention. The locations of the queue slots may be non-uniform
and variable given the dynamic environment of the warehouse. The
queue slots maybe offset according to a queuing algorithm that
observes the underlying global map and the existing obstacles and
constraints of the local map. The queuing algorithm may also
consider the practical limits of queuing in the space proximate the
target location/pose to avoid blocking traffic, interfering with
other locations, and creating new obstacles.
In addition, the proper queue slotting of robots into the queue
must be managed. In the example shown in FIG. 9, the robot with the
first priority to occupy the pose 602 is queued in the first queue
slot 610, while the other robots are queued in the other queue
slots based on their respective priorities. Priorities may be
determined by the order of the robots' entry into a zone 618
proximate pose 602 or other criteria, such as, order priority or
expedited delivery requirements (in the case of pick orders) or low
inventory (in the case of place orders). In this case, zone 618 is
defined by a radius, R, about pose 602, which in this case is
approximately three (3) meters (or 3.times.). The first robot to
enter the zone, in this case 604, has the highest priority and is
assigned the first queue slot, queue slot 610. When robot 606,
which is closer to zone 618 than robot 608, enters zone 618,
assuming that robot 600 is still at pose 602 and robot 604 is
located at queue slot 610, it has the next highest priority and it
is therefore assigned queue slot 612. When robot 608 then enters
zone 618, assuming that robot 600 is still at pose 602 and robots
604 and 606 are still located at queue slots 610 and 612,
respectively, it is assigned to queue slot 614.
When robot 600 moves from pose 602 (target location), robot 604
moves from queue slot 610 to pose 602. Robots 606 and 608 move to
queue slot positions 610 and 612, respectively. The next robot to
enter zone 618 would be positioned in queue slot position 614. Of
course, additional number of queue slot positions could be included
to accommodate expected traffic flows.
The manner in which the robots are navigated to the queue slots and
ultimately the target location is accomplished by temporarily
redirecting them from the pose of the target location to the
pose(s) of the queue slot(s). In other words, when it is determined
that a robot must be placed in a queue slot, its target pose is
temporarily adjusted to a pose corresponding to the location of the
queue slot to which it is assigned. As it moves up in position in
the queue, the pose is again adjusted temporarily to the pose of
the queue slot with the next highest priority until it is able to
reach its original target location at which time the pose is reset
to the original target pose.
Flow chart 700, FIG. 10, depicts the robot queuing process
implemented by WMS 15 or order server 14, as the case may be, for a
particular pose (target pose) within the warehouse. At step 702, it
is determined if the target pose is occupied by a robot. If it is
not, the process returns to step 702 until there is a robot
occupying the target pose. When a robot is occupying the target
pose, the process determines at step 704 if there is another robot
in the target zone or if there is a robot in one or more of the
queue slots. If it is determined that there is no robot in the
target zone or in one or more queue slots, the process returns to
step 702. If it is determined that there is a robot occupying the
target pose or if the queue slot(s) is/are occupied, then at step
706 the robots are assigned to the appropriate queue slots.
If there is a robot in the target zone but no robot in the queue
slots, then the robot in the target zone is directed to occupy the
first queue slot, i.e. queue slot 610, FIG. 9. If there is a robot
in the target zone and a robot (or multiple robots in the queue
slots) then the robot in the target zone is slotted into the next
available queue slot, as described above. If there is no robot in
the target zone but there is/are robot(s) in the queue slot(s),
then the slotted robots remain in the same positions. At step 708,
if it is determined that the target pose is not occupied, then the
robots in the queue slots are moved up a position, i.e. queue slot
610 to the target pose, queue slot 612 to queue slot 610 and so
forth. If the target pose is still occupied, the process returns to
step 704.
In FIG. 9, the queue locations 610, 612, and 614 are in line and
adjacent to each other. This is acceptable for many situations, but
in areas within a warehouse environment where there is limited
space or heavy traffic or when many queue locations are needed, it
may be desirable to utilize a "split" queue. An example of this is
shown in FIG. 11. Here, a processing station 800 having a target
location 802 is shown. Processing station 800 may be an induction
station attended by an operator where a robot is assigned a
customer order to fill and provided with a tote to carry the order
or it may be a packing station where the robot is dropping off a
customer order for packing and shipment by an operator. The target
location does not need to be associated with a station, but it is a
typical situation where multiple robots may be simultaneously vying
for a common target location.
Referring again to FIG. 11, queue locations 804, 806 and 808 are
part of a first queue group 810 and are shown spaced from target
location 802. In this example, additional queue locations are
required, but there is limited space as queue group 810 is adjacent
to a busy path of traffic traversed by robots, such as robot 814,
and operators. To overcome this issue, there is formed a second
queue group 816, including additional queue locations 818, 820, and
822, physically spaced from queue group 810 across path 812. The
queue locations in the two queue groups 810 and 816, even though
physically separated, together form a single queue for target
location 802. It should be noted that while there are two queue
groups each with three queue locations, any number of queue groups
having any number of queue locations may be used in accordance with
the disclosure herein.
Just as with FIG. 9, in the example of in FIG. 11, assuming the
target location 802 (labelled "T") is occupied by a robot being
serviced at station 802, robots entering a predefined target zone
803, defined by a dashed-line, are assigned to queue locations
based on priorities assigned to them by the system. Queue location
804, labelled "1", is the highest priority queue location. Queue
locations 806-822 have lower/decreasing priority levels, as
indicated by their labels "2"-"6". Thus, the robot with the first
or highest priority to occupy the target location 802, when it is
available, is directed to queue location 804, while the other
robots are queued in the other queue slots based on their
respective priorities. Priorities may be determined by the order of
the robots' entry into the predefined target zone. In other words,
the earlier the entry into the target zone, the higher the assigned
priority for the robot and thus the lower the queue number.
The assigned priorities may be established in other ways. For
example, instead of or in combination with the time of entering
into the target zone, priority can be assigned based on the
customer order of already picked items being carried by the robot
to a packing station for unloading, packing and shipping. The
customer order for each robot may be assigned a priority based on
one or more of the following criteria: shipping priority, item
type, customer type, or retailer, for example. Customer orders with
expedited delivery or preferred customers may be assigned a high
priority and therefore be placed in higher priority queue locations
to ensure faster processing. Similarly, certain products or
retailers could be given priority based on contractual
relationships. The priority of the customer order alone or in
combination with the priority based on the time of entering into
the target zone may be used to assign priority and hence queue
location to the robots vying for the common target location.
Continuing to refer to FIG. 11, there are shown two robots 824 and
826 which have entered the predefined target zone 803. Robot 824
has been assigned a priority of (1,B) and robot 826 has been
assigned a priority of (2,A). In this example the first priority
criteria is numerical and indicates the order in which the robots
entered the target zone 803, i.e. robot 824 entered first and robot
826 entered second. If the order of entry was the only criteria,
robot 824 would be assigned to queue location 804 and robot 826
would be assigned to queue location 806. However, in this example
there is a second criteria related to the customer order, e.g.
shipping priority, item type, customer type, or retailer. Robot 824
has been assigned a "B" priority regarding its customer order while
robot 826 has been assigned an "A" priority. In this example, the
customer order priority trumps the order of entry into the target
zone so, as indicted by lines 825 and 827, robot 824 is directed to
queue location 806 (location "2") and robot 826 is directed to
queue location 804 (location "1").
This above example is just one simple example of priority
assignment and any suitable method for assigning priority may be
used in connection with this invention using the standard queue
shown in FIG. 9, the split queue of FIG. 11 and the shared/split
queues described below in FIGS. 12 and 13.
In another embodiment, shown in FIG. 12, another aspect of the
disclosure is described. Here, a "shared" queue 830 may be used.
What is meant by "shared" in this context is that queue group 830
is shared among a number of target locations, such as target
locations 832, 834, and 836, which are associated with and
proximate to stations 838, 840, and 842, respectively. Robots that
are destined for any of target locations 832, 834 or 836 are
directed to one of the queue locations 850-858, which have
priorities 1-9, respectively. This means that queue location 850
(priority "1") is the location where the robot with the highest
priority would be located irrespective of the target location for
which it is destined and queue location 9 (priority "9") is the
queue location where the robot with the lowest priority would be
directed.
Stations 838 ("A"), 840 ("B"), and 842 ("C"), may be configured to
perform the same or different functions. For example, they may all
be configured as induction stations or packing stations or they may
be configured as a combination induction and packing stations.
Moreover, any number of stations and any number of queue locations
in queue group 830 may be used. In one scenario, stations 838, 840,
and 842 may be configured such that any robot in the queue
locations can proceed to any target location/station. In that case,
as indicated by solid line 864, a robot positioned in queue
location 850 would proceed to the first available target location
which in this example is target location 832. Target locations 834
and 836 are shown to be occupied by robots 860 and 862,
respectively. The robots in the other queue locations will all move
up to the next highest priority queue location.
Alternatively, for various reasons, certain robots may only be able
to proceed to certain stations/target locations. This scenario is
depicted in FIG. 12 by the dashed line 866, which shows the robot
in queue location 851 (priority "2") proceeding to open target
location 832 instead of the robot in queue location 850 (priority
"1"). This may be because the robot at queue location 850 is not
able to be serviced by station 838 (e.g. the robot needs to be
inducted but station 838 is dedicated to packaging/delivery). As
shown by dashed line 868, when robot 860 leaves target location 834
(assuming that robot 860 leaves before robot 862), the robot at
queue location 850 will proceed to target location 834 to be
serviced by station 840.
In yet another embodiment, there is shown in FIG. 13 the shared
queue 830 of FIG. 12 divided into a split queue having queue groups
830a and 830b. This shared queue will operate in the same manner as
the shared queue 830 of FIG. 12; however, it is split into two
queue groups due to the proximity of path 870, which is traversed
by operators and robots, such as robot 872. The first queue group
830a has queue locations 850-855 on one side of path 870 and a
second queue group 830b has queue locations 856-858 on the opposite
side of path 870. The queue locations in the two queue groups 830a
and 830b, even though physically separated, together form a single
queue for target locations 832, 834, and 836.
Referring now to FIG. 14, another aspect of the invention using the
"split" queue depicted in FIG. 11 is described. In this embodiment,
there is a processing station 900, which may be used to process
(induct or pack) the robots, which has two target processing
locations/positions 902a and 902b, instead of just one target
processing location/position 802 as shown in FIG. 11. The
processing positions 902a and 902b are each defined by a pose, as
described above. With two processing positions at a station, two
robots may be brought to the station so that they can be processed
together more rapidly by one or more operators, such as operator
904, than if each robot directed to the processing station in
series.
Typically, one processing station will be configured to carry out
only one function at a time, either induction or packing; however,
it is possible to carry out both functions at a single station.
Depicted at station 900 are several totes/tote arrays 905a-905c,
which the operator may select and use to induct robots being
assigned pick orders. One process of inducting robots which may be
implemented is described in U.S. patent application Ser. No.
15/254,321, entitled Item Storage Array for Mobile Base in Robot
Assisted Order-Fulfillment Operations, filed on Sep. 1, 2016, and
incorporated herein by reference in its entirety. Alternatively,
when a robot is arriving with a tote/tote array containing items
from one or more orders which have already been picked, operator
904 will unload the tote/tote array for packing and shipping of the
orders.
Moreover, while processing station 900 is shown to include two
processing positions, it is possible to configure station 900 to
have additional stations. As described below in more detail, with
multiple robots being directed in a coordinated manner from a queue
to a single processing station, such as station 900, the robots can
be more rapidly processed by operator 904. The result is less robot
downtime and hence increased productivity and throughput for the
overall order fulfillment warehouse.
In this embodiment, the queue is formed as a split queue having two
queue groups; namely, queue groups 906 and 908. Robots arriving at
a predetermined target zone proximate the poses for processing
positions 902a and 902b will be guided into either queue group 906
or 908 if the processing position is occupied or there are other
robots in the queue. If no other robot is in the target processing
position and no robots are in the queue groups, the robot may
proceed directly to the target processing position.
Queue group 906 may be located more closely to processing position
902a and queue group 908 may be located more closely to processing
position 902b so that the robots that are queued in queue group 906
may be more readily directed to processing position 902a and the
robots that are queued in queue group 908 may be more readily
directed to processing position 902b.
While the robots may be placed in the queue groups and directed out
of the queue groups to the processing positions in any desired
manner a preferred approach is depicted in FIG. 14. Queue location
910 in queue group 906 is shown to have a priority "1" which is the
highest priority. In Queue group 908, queue location 913 is
assigned priority "2" which is the next highest priority. The
priority assignments alternate between queue groups, with priority
"3" being in queue location 911 adjacent to queue location 910 in
queue group 906 and priority "4" being in queue group 908 at queue
location 914 adjacent to queue location 913. Finally, priority "5"
is located at queue location 912 adjacent queue location 911 in
queue group 906 and priority "6" is located at queue location 915
adjacent queue location 914 in queue group 908.
When robots destined for processing station 900 arrive in a
predetermined target zone proximate processing station 900 they are
placed into the queue groups 906 and 908 in an alternating manner
based on priority starting with the highest priority robot being
assigned to the queue location 910 of queue group queue group 906
and the next highest priority robot being queued at queue location
913 of queue group 908 and so on. When the processing positions
902a and 902b of processing station 900 are open/available, the
robots queued at queue locations 910 and 913 are directed,
respectively, to processing locations 902a and 902b. Robots located
at queue locations 911 and 914 may then be directed to move up in
priority to queue locations 910 and 913, respectively. Similarly,
Robots located at queue locations 912 and 915 may then be directed
to move up in priority to queue locations 911 and 914,
respectively, leaving room in the queue for new robots entering the
predetermined target zone to be queued. Of course, the queue may
contain additional queue locations if a greater volume of robots is
expected to be entering the queue at any given time. Additionally,
it is possible to dynamically adjust the queue size over time based
on machine learning.
In another embodiment, shown in FIG. 15, a "shared" queue 930 may
be used. As with the queue in FIG. 12, what is meant by "shared" in
this context is that queue group 930 is shared among a number of
processing stations, such as processing stations 932, 934, and 936,
each having two processing positions at which robots will be
located for operators to process. At processing station 932 there
are processing positions 931 and 933 which are processed by
operator 940. At processing station 934 there are processing
positions 935 and 937 which are processed by operator 942. And, at
processing station 936 there are processing positions 939 and 941
which are processed by operator 944.
As with the embodiment of FIG. 14, in this embodiment, one station
will typically be configured to carry out only one function at a
time, either induction or packing; however, it is possible to carry
out both functions at a single station. Depicted at station 932,
934, and 936 are several totes/tote arrays at each station; namely,
totes/tote arrays 950a-905c, 952a-c, and 954a-c, respectively,
which the operators will select and use to induct robots being
assigned pick orders.
Robots that are destined for any of processing stations 932, 934,
or 936 which have entered the predetermined target zone are
directed to one of the queue locations 960-968, which have assigned
priorities 1-9, respectively. This means that queue location 960
(priority "1") is the location where the robot with the highest
priority would be located irrespective of the processing station
for which it is destined and queue location 9 (priority "9") is the
queue location where the robot with the lowest priority would be
directed. While the robots may be placed in queue 930 and directed
out of the queue 930 to the processing positions in any desired
manner a preferred approach is depicted in FIG. 15.
As robots enter the predetermined target zone they are placed in
queue 930 in the appropriate queue location 960-968 based on
priority (1-9). Of course, the queue may contain additional queue
locations if a greater volume of robots are expected to be entering
the queue at any given time. Additionally, it is possible to
dynamically adjust the queue size over time based on machine
learning.
When the processing positions of each processing station 932 934,
936 are open/available, the robots queued in queue 930 may be
directed to the appropriate processing positions. For example, when
processing positions 931 and 933 of processing station 932 are
open, the two highest priority robots located at queue locations
960, 961 may be, respectively, directed thereto. When processing
positions 935 and 937 of processing station 934 are open, the next
two highest priority robots which are located at queue locations
962, 963 may be, respectively, directed thereto. Similarly, robots
located at queue locations 964 and 965 may then be directed to move
processing positions 939 and 941 (when open/available) of
processing station 936. As robots are moved from queue locations to
processing positions, the robots remaining in queue will be shifted
up to higher priority queue locations. In the above described
example, robots in queue locations 966, 967, 968 (priorities 7-9)
would be shifted up to queue locations 960, 961, 962 (priorities
1-3).
In yet another embodiment, there is shown in FIG. 16 the shared
queue 930 of FIG. 15, however, in this example it is divided into a
split queue having two queue groups 930a and 930b. This shared
queue will operate in the same manner as the shared queue 930 of
FIG. 15; however, it is split into two queue groups due to the
proximity of path 970, which is traversed by operators and robots,
such as robot 972. The first queue group 930a has queue locations
960-965 on one side of path 970 and a second queue group 930b has
queue locations 966-968 on the opposite side of path 970. The queue
locations in the two queue groups 930a and 930b, even though
physically separated, together form a single queue for processing
stations 932, 934, and 936. The robots are directed from the queue
groups 930a and 930b to the processing station 932, 934, and 936 in
the manner described above with regard to FIG. 15.
Referring now to FIG. 17, there is shown the split queue of FIG. 14
having two queue groups; namely, queue groups 906 and 908. However,
in this example, the queue is also operated as a "shared" queue,
i.e. it is shared among a number of processing stations, such as
processing stations 932, 934, and 936, each having two processing
positions at which robots will be located for operators to process.
Robots arriving at a predetermined target zone proximate the
processing stations they will be guided into either queue group 906
or 908. As described above with regard to FIG. 14, queue location
910 in queue group 906 is shown to have a priority "1", which is
the highest priority. In queue group 908, queue location 913 is
assigned priority "2" which is the next highest priority. The
priority assignments alternate between queue groups, with priority
"3" being in queue location 911 adjacent to queue location 910 in
queue group 906 and priority "4" being in queue group 908 at queue
location 914 adjacent to queue location 913. Finally, priority "5"
is located at queue location 912 adjacent queue location 911 in
queue group 906 and priority "6" is located at queue location 915
adjacent queue location 914 in queue group 908.
As with the embodiments of FIGS. 15 and 16, when the processing
positions of each processing station 932 934, 936 in FIG. 17 are
open/available, the robots queued in queue groups 906 and 908 may
be directed to the appropriate processing positions. For example,
when processing positions 931 and 933 of processing station 932 are
open, the two highest priority robots, i.e. those located at queue
locations 910 and 913 may be, respectively, directed thereto. As
the processing positions at the other processing stations open up,
the queued robots are directed in pairs in priority order from the
queue to the open positions. As with the other queue
configurations, as queue locations become available new robots from
lower priority locations in the queue are shifted to the
open/higher priority queue locations.
Of course, the examples depicted in FIGS. 15-17 are fairly simple
examples of how the invention may be implemented to direct pairs of
robots from queue locations to open processing positions at a
common processing station. Those skilled in the art will appreciate
that the processing positions will not always become open or
available in such an orderly fashion. In other words, each pair of
processing positions at a processing station may not become
available at the same time and robots located adjacent to each
other (i.e. in priority sequence) in the queue need not be directed
together (in parallel) to a processing station. The invention may
be configured to operate in a more dynamic way such that as
individual processing positions open up at different processing
stations, the robots may be directed individually, in priority
order, from the queue to the next available processing position
regardless of the processing station. It should be noted that the
type of processing required for each robot must be considered when
robots from the queue to the next available processing position to
ensure the processing station has the required processing
capability.
For example, a robot may need to be inducted to execute one or more
pick orders but the next available processing position may be
located at a station that is configured to only perform
unloading/packing. In this case, such robot may be by-passed in
favor of a robot in a lower priority queue location because it is
the highest priority robot that needs to be unloaded/packed.
While the foregoing description of the invention enables one of
ordinary skill to make and use what is considered presently to be
the best mode thereof, those of ordinary skill will understand and
appreciate the existence of variations, combinations, and
equivalents of the specific embodiments and examples herein. The
above-described embodiments of the present invention are intended
to be examples only. Alterations, modifications and variations may
be effected to the particular embodiments by those of skill in the
art without departing from the scope of the invention, which is
defined solely by the claims appended hereto. The invention is
therefore not limited by the above described embodiments and
examples.
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